Supporting Information
Catalytic Performance Comparison of Shape-Dependent Nanocrystals
and Textured Ultra Thin Films of Pt4Cu Alloy in the Formic Acid
Oxidation Process
L. Bromberg1, M. Fayette1, B. Martens1, Z. Luo2, Y. Wang1, D. Xu1, J. Zhang1,
J. Fang1*, and N. Dimitrov1**
1)
Department of Chemistry, State University of New York at Binghamton, PO Box 6000,
Binghamton, New York 13902 (USA)
2)
Microscopy and Imaging Center and Materials Science and Engineering Program, Texas
A&M University, College Station, Texas 77843
Phone: +1 (607) 777-3752*; +1 (607) 777-4271**
Fax: +1 (607) 777-4478
Email: jfang@binghamton.edu;* dimitrov@binghamton.edu**
URL: http://nano.binghamton.edu ; * http://chemiris.chem.binghamton.edu/DIMITROV/dimitrov.htm**
Item #1. EDS Analyses of Pt4Cu Nanopolyhedra: A typical spectrum and full data of
EDS@TEM analysis on each sample using a Ted Pella Ni grid are presented as follows.
Pt4Cu Nanoctahedra:
Sample: JF60(E1)
Processing option: All elements analyzed (Normalized), All results in atomic%
Spectrum
In stats.
Cu
W
Spectrum 1
Yes
17.97 1.86
Pt
80.18
S1
Spectrum 2
Spectrum 3
Spectrum 4
Spectrum 5
Yes
Yes
Yes
Yes
18.24
19.16
18.90
14.48
2.58
2.08
3.07
2.20
79.18
78.75
78.03
83.32
Mean
17.75 2.36 79.89
Std. deviation
1.89 0.47 2.07
Max.
19.16 3.07 83.32
Min.
14.48 1.86 78.03
-------------------------------------------------------------------------------Pt4Cu Nanocubes:
Sample: JF31_2A4
Processing option: All elements analyzed (Normalized), All results in atomic%
Spectrum
In stats.
Cu
Pt
Spectrum 1
Spectrum 2
Spectrum 3
Spectrum 4
Spectrum 5
Yes
Yes
Yes
Yes
Yes
11.26
15.25
17.06
16.80
14.20
88.74
84.75
82.94
83.20
85.80
14.91
2.35
17.06
11.26
85.09
2.35
88.74
82.94
Mean
Std. deviation
Max.
Min.
S2
Item #2. H UPD CV curves registered throughout the long-term formic acid oxidation
testing.
0.4
0.4
b)
0.2
0.2
0
0
I (mA)
I (mA)
a)
-0.2
-0.4
0
0.2
0.4
Initial
5,000 cycles
8,500 cycles
12,000 cycles
-0.4
Initial
1,400 cycles
2,400 cycles
-0.6
-0.8 -0.6 -0.4 -0.2
-0.2
-0.6
-0.8 -0.6 -0.4 -0.2
0.6
0
0.2
0.4
0.6
E (V), SSE
E (V) vs SSE
Figure 2S. CV curves for (a) Pt4Cu NO and (b) Pt4Cu NC catalysts in 0.1 M HClO4 in
the course of long-term cycling in formic acid. Scan rate: 0.050 V/s.
Item #3. Formic acid oxidation CV curves registered throughout the long-term
formic acid oxidation testing.
14
12
25
Initial
1,400 cycles
2,400 cycles
a)
20
8
I (mA)
I (mA)
10
6
Initial
5,000 cycles
8,500 cycles
12,000 cycles
b)
)
15
10
4
5
2
0
-0.6 -0.4 -0.2
0
0.2 0.4 0.6 0.8
E (V), SSE
1
0
-0.6 -0.4 -0.2
0
0.2 0.4 0.6 0.8
1
E (V), SSE
Figure 3S. CV curves for (a) Pt4Cu NO and (b) Pt4Cu NC catalysts in the course of
Long-term cycling in 0.1 M HClO4 + 2.0 M HCOOH. Scan Rate – 0.050 V/s.
S3
Item #4. Durability of thin film and bulk Pt catalysts assessed in formic acid
oxidation long-term testing.
140
bulk Pt
5R
15 R
120
% Activity
100
80
60
40
20
0
0
10
20
30
40
50
t (h)
Figure 4S. Decay of the catalytic activity for Pt thin films deposited by 5 (red) and
15 (blue) SLRR events and bulk Pt (black) catalysts.
S4
Item #5. Amount of Pt in Nano-octahedra (NO) and Nanocubes (NCs).
In order to determine the amount of catalyst present in the nanoparticles, it was assumed for the
sake of calculation that the catalyst contained only platinum, and lastly that the particles did not
overlap. The figure below presents a schematic of NO and NCs indicating the dimesions as
reported in the main text of this article.
9.2 nm
8.0 nm
9.2 nm
Nano –octahedron
Nanocube
http://en.wikipedia.org/wiki/File:Octahedron.svg
http://en.wikipedia.org/wiki/File:Hexahedron.svg
1.) Volume of the nanoparticles and number of Pt atoms per particle
𝑉𝑐𝑢𝑏𝑒𝑠 = (8.0 𝑥 10−7 𝑐𝑚)3 = 5.1 𝑥 10−19 𝑐𝑚3
𝑉𝑁𝑂 =
√2
(9.2 𝑥 10−7 𝑐𝑚)3 = 3.7 𝑥 10−19 𝑐𝑚3
3
𝑃𝑡𝑁𝐶 = 5.1 𝑥 10−19 𝑐𝑚3 𝑥
𝑃𝑡𝑁𝑂 = 3.7 𝑥 10
−19
21.5 𝑔 1 𝑚𝑜𝑙𝑒 6.022 𝑥 1023 𝑎𝑡𝑜𝑚𝑠
𝑎𝑡𝑜𝑚𝑠
𝑥
𝑥
= 3.4 𝑥 104
3
𝑐𝑚
195.1𝑔
1 𝑚𝑜𝑙𝑒
𝑁𝐶
21.5 𝑔 1 𝑚𝑜𝑙𝑒 6.022 𝑥 1023 𝑎𝑡𝑜𝑚𝑠
𝑎𝑡𝑜𝑚𝑠
4
𝑐𝑚 𝑥
𝑥
𝑥
=
2.5
𝑥
10
𝑐𝑚3 195.1𝑔
1 𝑚𝑜𝑙𝑒
𝑁𝑂
3
S5
2.) Surface area per particle and total number of particles in our experiment
The surface area of each particle type was calculated only for 5 sides (NCs) and 7 sides (NO) as
one side must remain in contact with the substrate. In order to ascertain the amount of each
particle, the ECASA for each type (5.6 cm2 for NC and 3.8 cm2 for NO) was used assuming that
the H UPD layer fully coated the entire particle.
𝐴𝑐𝑢𝑏𝑒𝑠 = 5(8.0 𝑥 10−7 𝑐𝑚)2 = 3.2 𝑥 10−12 𝑐𝑚2
7
𝐴𝑁𝑂 = (4)√3(9.2 𝑥 10−7 𝑐𝑚)2 = 2.6 𝑥 10−12 𝑐𝑚2
5.6 𝑐𝑚2
= 1.8 𝑥 1012 𝑐𝑢𝑏𝑒𝑠
3.2 𝑥 10−12 𝑐𝑚2⁄
𝑁𝐶
3.8 𝑐𝑚2
=
= 1.5 𝑥 1012 𝑜𝑐𝑡𝑎ℎ𝑒𝑑𝑟𝑎
2.6 𝑥 10−12 𝑐𝑚2⁄
𝑁𝑂
#𝑐𝑢𝑏𝑒𝑠 =
#𝑁𝑂
3.) Number of Pt monolayers (ML) per 1 cm2 electrochemically active surface area
With all the above information, we will now determine the amount of catalyst in terms of the
number of monolayers (ML’s) in order to compare the amount of catalyst present in the
nanoparticles to the thin films which are approximately 7-8 ML’s thick and that 1 ML of Pt is 1.5
x 1015 atoms/cm2 for the (111) face and 1.3 x 1015 atoms/cm2 for the (100) face.
𝑀𝐿𝐶𝑢𝑏𝑒𝑠 = 1.8 𝑥 1012 𝑐𝑢𝑏𝑒𝑠 𝑥 3.4 𝑥 104
1.1 𝑥1016 𝑎𝑡𝑜𝑚𝑠⁄
𝑎𝑡𝑜𝑚𝑠 6.1 𝑥 1016 𝑎𝑡𝑜𝑚𝑠
=
=
𝑐𝑢𝑏𝑒
5.6 𝑐𝑚2
2
= 1.3 𝑥1015 𝑎𝑡𝑜𝑚𝑠 𝑐𝑚 = 𝟖. 𝟓 𝑴𝑳
⁄𝑐𝑚2
12
𝑀𝐿𝑁𝑂 = 1.5 𝑥 10
1.0 𝑥1016 𝑎𝑡𝑜𝑚𝑠⁄
𝑎𝑡𝑜𝑚𝑠 3.8 𝑥 1016 𝑎𝑡𝑜𝑚𝑠
𝑁𝑂 𝑥 2.5𝑥 10
=
=
𝑁𝑂
3.8 𝑐𝑚2
4
2
= 1.5 𝑥1015 𝑎𝑡𝑜𝑚𝑠 𝑐𝑚 = 𝟔. 𝟕 𝑴𝑳
⁄𝑐𝑚2
Item #6. H UPD CV curves on single-crystalline Pt (hkl) electrodes.
S6
150
150
b
Current Density (A.cm )
100
-2
-2
Current Density (A.cm )
a
50
0
-50
-100
-150
-200
-0.8
-0.6
-0.4
-0.2
0
0.2
100
50
0
-50
-100
-150
-0.8
0.4
-0.6
-0.4
E (V), SSE
-0.2
0
0.2
0.4
E (V), SSE
100
-2
Current Density (A.cm )
c
50
0
-50
-100
-150
-200
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
E (V), SSE
Figure 5S. HUPD on Pt (hkl): a)(111), b)(100) and c)(110); Scan Rate: 0.050 V/s
Solution: 0.5 M H2SO4
S7